Due to a magnetic and electric coupling between two contact pairs, a contact pair induces a current or influences electric charges in adjacent contact pairs, so that side-to-side crosstalk occurs. To avoid the near-end crosstalk, the contact pairs may be arranged at very widely spaced locations from one another, or a shielding may be arranged between the contact pairs. However, if the contact pairs must be arranged very close to one another for design reasons, the above-described measures cannot be carried out, and the near-end crosstalk must be compensated.
The electric patch plug used most widely for symmetric data cables is the RJ-45 patch plug, which is known in various embodiments, depending on the technical requirement. Prior-art RJ-45 patch plugs of category 5 have, e.g., a side-to-side crosstalk attenuation of &gt;40 dB at a transmission frequency 100 MHz between all four contact pairs. Based on the unfavorable contact configuration in RJ-45, increased side-to-side crosstalk occurs due to the design. This occurs especially in the case of the plug between the two pairs 3, 6 and 4, 5 because of the interlaced arrangement (e.g. EIA/TIA 568A and 568B). This increased side-to-side crosstalk limits the use at high transmission frequencies. However, the contact assignment cannot be changed for reasons of compatibility with the prior-art plugs. Due to this unfavorable design arrangement, special measures are needed even to reach a near-end crosstalk of &gt;40 dB at 100 MHz of category 5. All prior-art measures leave the plug unaffected and bring about the improvement in near-end crosstalk by compensatory measures in the socket (jack).
The crossing of a pairs (pairs of conductive paths) has been used. As a result of this side-to-side crosstalk, an antiphase is generated behind the crossed area. This is also described as balancing the circuits. The conductive path of each transmission line connecting to the jack/plug (e.g. two conductive paths per transmission line--a pair) that is furthest from the adjacent pair in the jack/plug is brought together with the conductive path of that adjacent pair which is closest (a twist of the initial position). This use of conductive paths (e.g. in a circuit board) balances the reactive effect of pair interaction at the jack/plug. Crossing of the two lines 4 and 5 is described in this connection in EP 0 525 703 A1, and the crossing of the two lines 3 and 6 in WP 94/06216. The twisting of leads of different pairs has also been known from EP 0 601 829 A2. The compensation by direct auxiliary capacitances to the contact after next can be found in EP 0 692 884 A1. A solution for compensation by extended and multiply bent contacts to their crossing is described in EP 0 598 192 A1, where the compensation is generated behind the crossing by the continued contacts and insulation displacement terminals.
Compensation measures in the socket (jack) are a common feature of all the prior-art solutions, but the distance between the side-to-side crosstalk area and the effective compensation area is too great. To achieve the spring forces of the jack/socket and to securely lead the mobile contacts in the socket these contacts are made relatively long. This entails a compensation region--a crossing on a printed circuit board, on the extended stationary contacts or twisted terminal leads--used at far too great a distance. The gain from these prior-art compensation measures is therefore limited, so that patch plugs for 200 MHz cannot be prepared according to these prior-art solutions, because the near-end crosstalk cannot be sufficiently compensated at higher frequencies.